Method of and apparatus for making plastic articles



L. D. SOUBIER Feb. 6, 1962 METHOD OF AND APPARATUS FOR MAKING PLASTICARTICLES Filed March 17, 1959 9 Sheets-Sheet 1 J en. Hu f /W R .e u m mm A w MW, 4 I d n kmwsww w K m j e Im C z Y f B NMQWN J M y hmz.

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Feb. 6, 1962 L. D. SOUBIER METHOD OF' AND APPARATUS FOR MAKING PLASTICARTICLES Filed March 17, 1959 EEZ 9 Sheets-Sheet 2 INVENTOR L. D.SOUBIER Feb. 6, 1962 METHOD OF' AND APPARATUS FOR MAKING PLASTICARTICLES Filed March 17, 1959 9 Sheets-Sheet 3 INVENTOR Leonard SozLz'ern BY I lmzwxzw@ fag/yr Feb. 6, 1962 1 D. SOUBIER 3,019,480

METHOD oF AND APPARATUS POR MAKING PLASTIC ARTICLES Filed March 17, 19599 Sheeis-Sheet 4 INVENTOR Leona ra'. 'OZLbz'r Armen/0f L. D. SOUBIERFeb. 6, 1962 9 Sheets-Sheet 5 Filed March 1'7, 1959 INVENTOR 3 n m K, T@E1 ww .l W n| T A ;1 l il e, Q f 2 f /a 7 5 5 3 u W Leonamoubzer Feb.6, 1962 l.. D. SOUBIER 3,019,480

METHOD OF' AND APPARATUS FOR MAKING PLASTIC ARTICLES Filed March 17,1959 9 SheetS-Sheet 6 INVENTOR Leonard/. Salzbz'er BY M Feb. 6, 1962 D.SOUBIER 3,019,480

METHOD OF AND APPARATUS FOR MAKING PLASTIC ARTICLES Filed March 17, 19599 Sheets-Sheet 7 INV ENTOR Feb. 6, 1962 D. SOUBIER 3,019,480

METHOD OF' AND APPARATUS FOR MAKING PLASTIC ARTICLES Filed March 17,1959 9 Sheets-Sheet 8 .f7-0p of INVENTOR Leona/d Joaz'ef' Feb. 6, 1962l.. D. SOUBIER 3,019,480

METHOD 0F AND APPARATUS FOR MAKING PLASTIC ARTICLES Filed March 1'7,1959 9 Sheets-Sheet 9 INVENTOR Leona/d 50u52 6i' 3,019,480 METHQD @E ANDAPPARATUS FOR MAKING PLASTIC ARTICLES Leonard D. oubier, rll`oledo,Ohio, assigner to @wens- Illinois Glass Company, a corporation of OhioFiled Mar. i7, 1959, Ser. No. '799,909 Claims. (Cl. :t3- 5) The presentinvention relates to a method of and apparatus for making plasticarticles by a combined injection, extrusion and blowing process, andmore particularly to the formation of a blank from which the majorportion of a plastic container or the like is subsequently blown.

In the manufacture of plastic containers or the like articles, it hasbeen proposed that a process be utilized which includes the steps ofinjection molding a finished article portion, such as the neck of acontainer, extruding a tubular portion to form a blank, and finallyblowing the formed tubular blank to tinal configuration. In the blowingof any articles, such as glassware, containers or the like, it isaxiomatic that the final article is only as good as the blank from whichit is blown. Thus it is vital that the blank be shaped and formed toinsure the best possible material distribution in the final article, toprovide suiiicient material for iinal articlestrength without wastingmaterial, and to accommodate rapid and efticient blowing to final sizeand conguration.

The present invention is concerned primarily with a means and a methodfor the formation of a blank satisfying the exacting, but eminentlypractical, requirements set forth above, while at the same time beingeconomically feasible from an operational standpoint, i.e., capable ofbeing carried out within a limited period of time constituting only afraction of the complete forming cycle. The broadest aspect of thepresent invention resides in the provision of a blank tailored to thesize and configuration of the article to `be formed. t

In a finished container having a blown body portion of larger dimensionsthan the neck mold thereof, the greatest amount of material should beincorporated at the upper end portion of the body, i.e., at the shoulderor neck-tobody transition portions of the body, particularly since theseportions are displaced substantially radially of the container axisduring blowing, thus materially reducing the nal wall thickness thereof.TheV problem is particularly acute at the corner portions of a square orrectangular body portion. The medial portions of the blank form the sidewalls of the container and these portions may be of somewhat reducedthickness. The bottom portions are normally formed by pinching the blankshut and better radial distribution is obtained at the bottom.

Since the extruded blank is generally tubular in configuration with theextrusion taking place through a fixed, generally annular orifice undersubstantially constant extrusion pressures exerted at a location remotefrom the orifice, with the upper end of the extruded tube being formedintegrally with the injection molded neck, the thickness of the tubingextruded through the orifice is primarily a function of the speed ofmovement of the injection molded neck away from the orifice. Generally,the more slowly the neck mold is moved away from the orifice, thethicker will be the walls of the extruded tubing. Conversely, if theneck mold is moved away from the orifice at a speed greater than thenormal rate of extrusion effective to form a tube of nominal wallthickness, the wall thickness will be reduced and a thinner walled tubeportion will be expressed through the orifice.

This effect is utilized in the instant invention to control the wallthickness of the tube from which the final container body or the like isto be blown. Initially, the extrusion of the tube takes place as` theneck mold is re- Vnited ftates @arent dld Patented Feb. 6, 1962 tractedor moved away from the extrusion orifice at a rate of speed which isrelatively low, so that a relatively thick length of tubing is initiallyformed. After the initially thick length of tubing has been formed of anaxial extent suliicient to provide the upper or shoulder portions of thefinished container, the speed of tube expression through the orifice isincreased so that a thinner section of tubing is extruded to provide aportion corresponding, in the finished container, to the side walls andbottom of the container.

It is, therefore, an important object of the present invention toprovide a method of and apparatus for forming a tubular blank ofpredetermined shape from which a plastic article is subsequently blown.

Another important object of the present invention is the provision of amethod of forming a hollow plastic arti-- cle from an extruded tube ofvariant wall thickness from which a hollow plastic article issubsequently blown,

A further important object of this invention is the provision of anapparatus for withdrawing an injection mold from an annular orifice atdifferent rates of speed along the direction of travel thereof to form atubular extension of variant wall thickness.

Yet another object is the provision of a method of making a blownplastic article by the injection molding of a tinished portion of thearticle, the subsequent movement of the injection mold from an annularorifice at different rates of speed to vary the wall thickness of a tubeformed integrally with the material filling the injection mold, andblowing the tube to its final configuration.

Other objects and advantages of the invention will appear from thefollowing detailed description taken in conjunction with the annexeddrawings, in which:

On the drawings:

FIGURE l is a schematic View of a machine of the present invention;

FIGURE 2 is a vertical fragmentary sectional View taken through anextrusion orifice of the machine;

FIGURE 3 is a View similar to FIGURE 2 illustrating a portion of themachine in an operated position;

FIGURE 4 is an end View, with parts `broken away, and in section ofthemachine;

FIGURE 5 is an enlarged sectional View taken on the plane 5 5 of FIGURE4;

FIGURE 6 is a view taken along the plane --d of FIGURE 5;

FiGURE 7 is a View similar to FIGURES 2 and 3 illustrating the apparatusin another adjusted position;

FIGURE 8 is an electrical wiring diagram schematically illustrating theelectrical control system of the machine; and

FIGURE 9 is a fragmentary hydraulic diagram schematically showing thehydraulic control system of the machine.

General operation FIGURE l of the drawings is a schematic overall viewof the apparatus of the present invention and well illustrates themethod of the present invention.

It will be noted that the machine includes generally a recirculatingextruder-plasticizer, Vincluding a displaceable recirculation piston, atwo-part sleeve valve and internal injection piston assembly, meansdefining an orifice through which the plasticized material is expressed,a neck mold within which a finished portion of an article, such as theneck of a container, is formed, and separable blow1 molds within whichthe article is blown to its final form.

The apparatus of the present invention and the method of this inventionhave been developed primarily for the utilization of plasticizablematerials, preferably polyethylene or other similar thermoplasticmaterials.

Generally, the apparatus includes a hopper within which granularpolyethylene or similar material is stored and communicating at itslower end with an elongated chamber or barrel of theeXtruder-plasticizer. Disposed within the plasticizer barrel is aneatruder screw which rotates continuously to advance material to thedischarge outlet. As the material is advanced by the extruder screwwithin the plasticizer barrel, the material is worked under pressure andis subjected to heat to render the ma* terial plastic and in iiuid formas it issues from the free end of the extruder tube. The tree end of theeatruder barrel comrnunicates with a recirculation passage whichestablishes communication from the discharge end of the extruder screwto a portion of the barrel displaced longitudinally from the hopper andlocated at a point at which the material within the extruder barrel isreduced to a viscous, iluid state. Recirculation of material through therecirculation passage is controlled by a recirculation piston which issingle acting and which is fluid pressure actuated to supplement theextruder output during certain portions of the cycle and which alsoserve to control recirculation of the thermoplastic material.

The primary purpose of recirculation is to accommodate continuousoperation of the extruder screw and to accommodate continuouspiasticizing action without the necessity of halting and initiatingeXtruder operations with each molding and blowing cycle. ln effect, therecirculation passage forms a reserve or overiiow accumulator into whichthe output of the eXtruder screw flows when the extruder output is notbeing utilize this accumulator being vented back to the plasticizer.

The eXtruder and plasticizer output communicates with a restrictedannular oriiice through an elongated passage. Overlying this orice andin communication therewith is a neck mold formed of separable neck moldhalves. The neck or finish of the container is normally the mostcritical portion of the container, so far as dimensions are concerned,and in order to maintain these dimensions within the rather closetolerances required, the iinish is preferably injection molded. The neckmold thus becomes an injection mold. injection molding usually requirespressures different from those normally provided by a combinationextruder and plasticizer, and this different pressure is utilized onlyduring the injection molding step of the cycle. For such intermittentinjection operations, the apparatus of the present invention utilizes aninjection piston which is fluid-pressure displaceable into the conduitfilled with plasticized material intermediate the plasticizer output andthe orifice.

For the injection operation to be effective, the back flow of plastic tothe plasticizer must be prevented and a column of plasticized materialmust be isolated between the injection system 'and the neck mold. Thisisolation is carried out by a sleeve valve concentric with the injectionpiston and insertable into the plasticized material conduit. Further,this sleeve valve is closed at all times at which plastic material isnot being expressed through the orifice from the eXtmder-plasticizer. A.novel actuating means for sequentially actuating the sleeve valve andthe injection piston and also for operating the sleeve valveindependently of the piston is provided by the present invention.

Following the injection of the nish within the separable neck mold,extrusion of plasticized material from the eXtruder-plasticizer throughthe orifice occurs during elevation of the neck mold, so that anextruded tubular extension is formed integral with the material fillingthe neck mold. The vertical movement of the neck mold is carried out intimed, correlated sequence to the extrusion of the extension, so thatthe extension is of diiierential wall thickness throughout its length toprovide additional material at those portions of the finished containerwhich need such additional material.

Following the extrusion of the tubular extension and movement of theneck mold from its position overlying the orice, the tubular extensionis enclosed within a pair of separable blow molds and blow air or otherpressured Huid is introduced through the neck mold to blow th containerto its final coniiguration.

Finally, a container-severing and container-pickup apparatus is actuatedto remove the iinished article from the machine after the opening of theblow molds.

The complete apparatus is disclosed in the copending application ofRichard C. Alien and Leon E. Ephee, Serial No. 797,276, filed in theUnited States Patent Ofnce on March 4, 1959, and assigned to thelassignee of the present invention. The instant application is concernedprimarily with the vertical movement of the neck mold and the controlthereof.

Neck mold and actuating structure The flow of plasticized material fromthe plasticizer outlet is distributed to a plurality of oriices wir inan orifice block t? through cross channel l2@ (FGURE 2) and individualpassages i255. From each of the lateral passages "t28, the plasticmaterial passes through an annular ilow passage between a mandrel 95, anoriiice sleeve 9i `and an orifice nozzle N3 for issuance through theorifice lui.

As best illustrated in FlGURES 2, 3 and 7, each of the oriiices itil isdened by a cooperating mandrel and a nozzle Trtt, and each such oriiiceis adapted for he discharge of plastic material upwardly therethrough.During the injection of the neck or iinish of a container or the like,the orifice mit has superimposed thereon a neck moid indicated generallyat E56.

This neck mold is carried by the machine 'oase 35 through upper sideframes S6 (FIGURES 4 and 5), the side frames being joined by an uppersupport plate 151 upon which is mounted a vertically disposed neck moldactuating cylinder 1552. This neck mold cylinder l52 is surrounded by anupwardly extending frame 153 carrying a top support plate 154 on whichis superimposed a stop or check cylinder l55. As will be explained inconnection with the control system and operation of the device of thepresent invention, the stop cylinder iSS is adapted to receive iiuidunder pressure through line 345, the cylinder 155 being single actingand being urged downwardly by uid pressure, so that the actuating rod156 thereof abuts the upper extremity of the upper extension 57 of theactuating rod 153 of the cylinder 152. The cylinder 1 52 which controlsnormal movement of the neck mold is double acting and is actuated by uidpressure introduced thereinto through lines 365 and 333. The lower end15S of the piston rod of cylinder 152 is threadedly connected, as at159, with a neck mold guide block E69 guided by a vertical bore 161formed in a xed guided yoke M2 provided with oppositely laterallydirected pilot portions lof: each having a vertical aperture le@receiving a vertically disposed xed guide rod 165. The guide rods 16Sare secured in the apertures E64 and project vertically throughupstanding iixed guide bosses lti secured to the frame 86 (FIGURE 4).Fi`he guide yoke M2 is thus supported for vertical reciprocatingmovement from its lowered position (illustrated in FIG- URE 2 of thedrawings) to its raised position (illustrated in FIGURE 3 of thedrawings). The guide yoke 162 is actuated between these two positions bymeans of the actuating cylinder 152.

The guide yoke E62 carries a plurality of depending guide pins in? fixedto the yoke and depending into vertical apertures 16S formed in aradially enlarged embossment le@ formed at the lower end of the blocklett. The block le@ is urged to its illustrated lowered positionrelative to the guide yoke 1.62 by a plurality ot compression springs176i interposed therebetween and having their ends inserted intoopposing, aligned recesses ll, MZ.

The lower extremity of the block tot) is provided with an upwardlyextending recess 75 into which is threaded a sleeve 17o which iscentrally bored to receive the upper tubular end ZV77 of a verticallymovable neck mold mandrel 178. This neck mold mandrel is provided with acentral axial bore 180 through which blow air or other suitable fluidunder pressure can be introduced by means of a radial air passage 355.The iluid pressure supply system is illustrated in FIGURE 9 and ishereinafter described in greater detail. The bore 180 of the neck moldmandrel 178 is radially enlarged at its upper end to accommodate acompression spring 181, and this spring 181 normally urges the neck moldmandrel downwardly to engage a radial enlargement 182 within the chamber175 against the end of the threaded sleeve insert 176.

In addition to the axial bore 180, the neck mold mandrel 178 is providedwith a plurality of vertical passages 183 parallel to the bore 180 andcommunicating at their upper ends with outlet housings 184, as bestshown in FIGURE 2.

The spring pressed neck mold mandrel 178 is enclosed within a separableneck mold housing comprising two separable angle blocks 18S surroundingthe neck mold mandrel 178 and two semi-cylindrical half-molds 186cooperatively contoured, as at 186A, to dene the bottle finish. In theillustrated embodiment, these surfaces 186A are contoured tocooperatively deiine exterior threads, although other neck finishes maybe provided if such is desired. The neck molds 186 are mounted upon andcomovable with carriers 187, cru-movement of the mold halves 186 and thecarriers 187 being insured by cap screws 188. The separable carriers 187are provided with inclined recesses 189 within which are slidablydisposed similarly inclined guide pins 198 carried by the enlargedembossment 169 of the element 160. The carriers 187 are interposed`between side guide projections 191 formed on the guide yoke 162 andslots 187A receive projections and thus prevent vertical movement of thecarriers 187 and the molds 186 relative to the guide yoke, butaccommodates relative lateral separatory movement of the mold halves 186and the carriers 187.

The operation of the neck mold ofthe present invention will be readilyappreciated by comparison of FIGURES 2, 3 and 7, from which it will beseen that the neck mold is originally lowered to its position of FiGURE2 with the neck mold mandrel 178 contacting the free upper end of theorifice mandrel 95 and with the threaded neck recess deiined by thecylindrical outer surface of the neck mandrel 178 and the threadedcontour of the interior of the mold halves 186 registering with theorifice 1011. With the neck mold positioned in this manner, the cylinder65 is actuated to subject the plastic material to injection pressure,and plastic material will be injected into the finish mold, continedtherein, and injection molded to its iinished configuration. Next, thecylinder 152 is actuated to retract the piston rod 158 upwardly,elevating the guide yoke 162, the block 1611 and the neck mold 150 as aunit to the position of FIGURE 3. During this movement of the neck mold,the recirculation cylinder 47 is actuated and plastic material isextruded through the oriiice 1th) to form the tubular extension, as bestillustrated in FIGURE 3. During this movement, the speed of withdrawalof the neck mold 186 is governed by a series of limit switches arrangedvertically in sequence and supported by one of the cylindrical guidepost bushings 166, as illustrated in FIGURES 4 and 5. r.The actuation ofthese limit switches is carried out by an actuating arm 195 carried bythe adjacent guide projection 163. The specific operation of these limitswitches is illustrated in FiGURES 8 and 9 and described in detail inconnection therewith.

The extruded plastic tubular extension 2G() may thus be of varying wallthickness, the wall thickness varying inversely with the speed ofretraction of the piston-actuating rod 158. l

When the neck mold 151i has Ibeen retracted to its URE 4) of the stopcylinder 15e'. Upon release ot the stop cylinder, by means described inconnection with FIGURES 8 and 9, `further retraction of the piston rod158 is accommodated with consequent movement of the neck mold from itsposition of FIGURE 3 to its position of FIGURE 7. Such additionalmovement of the piston rod will open the neck mold because of abutmentbetween the plate 151 and the stops 156 carried thereby and theextensions 163 of the element 1160. Consequently, the guide block 162will be held in its position of FIGURE 3, while the element 166 will beretracted against the force of the compression springs 170. Thisretraction will cam the mold carrier blocks 187 laterally outwardlybecause of the inclination of the guide pins 19t), and the mold halves186 will be separated laterally from the finish 2111 previously moldedby injection. As a consequence of relative movement of the guide block162 and the element 161), the neck mold mandrel 178 is retracted fromthe inish 201 and the neck molds 186 are retracted laterally as abovedescribed, so that the bottle neck or finish is completely released andthe bottle is no longer carried by the neck mold.

Surmounting the free upper end of the actuating rod 157 of the neck moldcylinder 152 is a T-shaped plate 190 (FIGURES 5 and 6) movablevertically with the neck mold 15G. On this plate is a pivoted finger 191engageable with the actuating arm 193 of a limit switch LSS when theneck mold is in its position of FIGURE 3. The switch LSS functions ashereinafter more fully described and the utilization of the pivotedAlinger accommodates actuation of the switch only on the upper stroke ofthe cylinder 152.

Also carried by the plate 191B` is a second projection 192 (FIGURE 6)engageable with the actuating arm 194 of a limit switch LS6 when theneck mold is in its position of FIGURE 3. This switch L56 is a safetyinterlock to prevent timer actuation of the blow mold cylinders 220unless the neck mold is withdrawn upwardly, as hereinafter described indetail.

The plate 191i is provided with a vertical projection 196 for actuatingan upper limit switch L87 when the neck mold is in. its position ofFIGURE 7. rlfhis switch LS7 actuates the take-out return as hereinafterdescribed.

Intermediate the operational steps illustrated in FG- URES 2, 5 and 7 ofthe drawings, a pair of complementary blow mold sections 21@ are closedupon the tubular extension 211i) and air is introduced through the airpassage 355, the chamber 175, the axial passage 186 of the neck mandrel178 and into the interior of the tubular extension 21119. This blowingis eiicctive to form the finished container 202 by the blowing of thetubular extension Zilli against the complementary blow mold sections.The introduction of fresh air is accommodated by the escape of a portionof the blow air through the passages 183.

Electric and hydraulic control system FIGURES 8 and 9 of the drawingsillustrate schematically the electric and hydraulic control circuits.

As best illustrated in FIGURE 8 of the drawings, two electric motors arepreferably utilized, motor M1 driving the extruder screw and motor M2`driving a pair of hydraulic pumps P1 and P2 as best shown in FIGURE 9.These motors M1 and M2 receive three phase, sixty cycle, 220 voltelectric power from lines L1, L2 and L3 and this power is converted tovolt current through a transformer TR to supply said current to acontrol system through main lines L5 and L6. The motors M1 and M2 areprovided with conventional control circuits including one-way start andstop switches, the start switches being bridged by conventional holdingcircuits.

The control circuit incorporates two separate and distinct timers driventhrough timer motor TM1 and TM2. The initial phases of operation areunder the control of timer motor TM1 provided with an autocycle switch.This autocycle switch is bridged by a timer contact Z closed by themotor TMll, namely contact TAll, which cooperates with a contact TBdclosed by the timer motor TMZ to provide overlapping of the two timerphases upon recycling of the machine, as will be later explained.

To condition the machine for operation, it is essentiial that the neckmold 15d be in its down or lowered position, contacting the uppersurface of the orice block 103, so that the interior neck mold recesses87 are aligned with the orice lill. As best shown in FTGURE 9, thepositioning of the neck mold l@ in its down position is attained byactuating the primary neck mold piston 152 downwardly within itscylinder. This operation requires energization of the solenoid Sl. toactuate fourway valve Vl to the left against the 1cias of spring SP1 soas to interconnect the main hydraulic pressure line Pl with the upperend of the cylinder T52 for the neck mold 150. Actuation of the valve V1to the left will eitect fluid flow through fluid flow line 300,actuating to the right positioning cylinder 301 and displacing fluid owcontrol valve V2 to the right. In this manner, hydraulic line 302receives iluid under line pressure from the main pressure line Pll, thisflow being passed through valve V2 through line 303 and check valve 3Mto the upper end of the neck mold cylinder l52. Fluid displaced from thelower side of the neck mold piston by downward movement of the pistonwill be displaced through line 3i5, ow control valve 3% and lines 367and 308 to a sump or drain line 309 through the valve V2.

Returning now to FIGURE 8, it will be seen that the solenoid S1 for`depressing the neck mold 150 as heretofore described will be actuatedwhen limit switch LSS is actuated by retraction of the take-out 23d,timer contacts TAZ have been actuated by the timer motor TMI, `and limitswitch L84 responsive to full opening of the blow molds 210 has beenclosed.

After lowering of the neck mold 150 to its position immediatelyoverlying the orice, the next operation involves the injection of thecontainer nish by the displacement of plastic material under pressureinto the neck mold d. As illustrated in FTGURE 8, this operation iscarried out merely upon closure of primary contacts TAS driven by thetimer motor TMll to energize solenoid S2.

Simultaneously with the opening of the timer contact TAS and thede-energization of the Solenoid S2, timer contact TA4 is closed which,so long as limit switch L89 is closed by the presence of the neck mold150 in its down position, energizes the solenoid S3. This solenoid S3 isellective to terminate the injection molding operation and initiate theextrusion of the tube 2h10, as shown in FIGURE 3.

To accommodate the flow of material from the extruder screw and therecirculation piston the neck mold l5?, must be displaced upwardly.

To accommodate upward movement of the neck mold, as the extrusion of thetubular extension proceeds, the timer switch TAZ is de-energized,de-energizing the solenoid Sl. and allowing the valve Vl. to return toits illusrated right-hand position of FIGURE 9. At this time, the springSP1 returns the valve Vll to its right-hand position interconnecting theactuating cylinder 361 with a drain conduit D3 and connecting a secondactuating cylinder 33t) with the pressure conduit 39,32. Displacement ofthe valve V2 to the left results in the connection of the line 39S withthe rydraulic iluid under pressure in the line 362. Pressure within theline 368 opens the check valve 331 against the bias of its spring, thusbypassing the valve 366 and simultaneously exerting pressure on theunder side of the neck mold lift cylinder 152 and on the valve 3dethrough by-pass line 332 to elevate the valve 3% so as to accommodatethe interconnection of the pressure line 3% and the line 3%. Thus, huidpressure em'sts on the under side of the neck mold piston 15S urging thepiston upwardly, which pressure flows through valve 30e more easily thanthrough check valve 333i. Once pressure exists on both sides of thevalve 331, the check spring closes the valve.

Upward movement of the piston is resisted by back pressure generatedthereabove in the cylinder 152, this back pressure being generated bythe How of iluid through line 333 and a restricted orice 363 vented to adrain D4 through valve V2 and line 309 previously described.

Thus, the neck mold E50 will be displaced upwardly slowly during itsinitial movement due to the resistance to back pressure ow through therestricted oriiice 334. This slow initial movement of the neck mold 15Gis desirable to (l) provide a thicker wall section in that portion ofthe tubular extension Zitti corresponding to the shoulders of thefinished container and to (2) avoid the rupture of the material issuingfrom the oriiice ltti under the combined pressures exerted by theextruder screw 52 and the recirculation piston 456 from the materialpreviously injection molded in the neck mold 156.

As the neck mold 159 moves upwardly, the plate 195 attached theretocontacts limit switch LSltl, closing this limit switch and energizingsolenoid S4. This solenoid S4 is effective to displace to the left valveVS against the bias of spring SP6. Leftward movement of the valve V8will interconnect pressure line 336 and an actuating cylinder 337displacing the valve V7 to the right. Displacement of the valve V7 tothe right will interconnect line 363 and the drain D4 with aline 338 soas to accommodate ow through a second and larger oriiice 339. Theinterposing of the larger orifice 339 into the drain line of the neckmold cylinder 152 will oder less resistance to displacement of the neckmold cylinder upwardly and will result in upward travel of the neck moldi5@ at an increased rate of speed. Thus, the wall thickness of thetubular extension will be lessened.

As the neck mold 150 continues to move upwardly, the projecting plate Ton the neck mold actuating rod 158 closes limit switch LSS, and thislimit switch will initiate operation of the second timer by startingtimer motor TMZ.

lt will be noted that the solenoid S4 controlling actuation of the neckmold piston lSS by venting the back pressure effective thereon to drainis energized by the limit switch LSltl and not by a contact of the rsttimer TMll. Therefore, the neck mold l5@ continues to travel upwardly.

Upon opening of the timer contacts TA4, the solenoid S3 is de-energizedto cut off the flow of material to the orifice lill by means of thesleeve valve.

The neck mold 15@ continues to move upwardly,

retching slightly the previously extruded plastic material tubularextension Ztitl and such stretching continues until the upper stopextension 157 of the neck mold piston contacts the stop rod l5@ of thestop cylinder 155. The stretching of the tubular extension Ztltl resultsin the vformation of a uniform, truly vertical tube which is alignedwith the vertical axis of the mold and which can be blown to a uniformcontainer. The Stretching does not change any differential wallthickness in the tube, since substantially uniform longitudinal thinningof all wall thicknesses results. This stop rod T56 is extendeddownwardly inasmuch as pressure in the main line Pl iS passed by valveV9 through line 345 to the upper end of the cylinder, as shown in FTGURE20. Because of the pressure drop across the restricted oriiice 339, thepressure acting in the under side of the neck mold piston is less thanthe pressure acting upon the upper side of the stop cylinder, and thecylinder neck mold piston will no longer be displaced upwardly despitethe fact that there is full line pressure on the under side thereof.

As soon as the neck mold clears the upper extent or extremity of theblow molds, limit switch LSG is actuated to close the blow molds 2id bysolenoid S5.

This solenoid S5 remains actuated while a solenoid S6 is energized bytimer contact T53 to introduce expanding air through the hollow neckmold mandrel to expand the tubular extrusion against the inner wall sur-`faces of the blow molds. The blowing operation is a timed operation andthe op@ ning of the contact TBS will shut ofi the expanding air byde-energizing solenoid S6.

The blow air introduced through the neck mold 186 is under substantialpressure, ie., on the order of 100 pounds per sq. in., andlsubstantially instantaneous infia tion of the tube 25! will occur. Topromote cooling of the tube, circulation of this blow air isaccommodated through passages and valve housings i3d.

Subsequently and after the elapse of sufficient time to accommodatesetting of the heated material the opening ol the timer contacts TB?.will de-energize the solenoid S5, to open the blow molds. Opening of theblow molds actuates limit switch LSli ito its closed position. The limitswitch L37 was previously closed when the neck ring was moved to itsuppermost position. Upon closure of the timer contact TBS, solenoid S7is ener gized and the takeout is actuated to move the take-out inwardlybeneath the blown containers which are eX- posed when the molds open(FIGURE 7).

When the take-out is in its furthest position, limit switch LSS isactuated to energize relay CRZ and the energization of this relay willenergize solenoids SS and S9 and S10. Solenoid S8 is effective tointroduce infiating air into the resilient bags of the take-out therebyclamping the nished containers in the take-out. At the same time,solenoid S9 is energized to actuate valve V12 to the left against thebias of a spring `SPS moving actuating cylinder 350 to the right `andsimilarly moving valve V9. Valve V9 in its actuated right hand positioninterconnects the line 345 and a drain D6, thus removing the hold-downpressure on the neck mold holddown cylinder. This frees the neck moldfor further upward movement under the pressure in line 305. Tofacilitate the rapid upward movement of the neck mold, solenoid Siti isenergized to displace valve V13 to the left against the bias of springSU9, so that actuating cylinder 351 can displace valve Vit/i to theright interconnecting the back pressure line 333 with a drain D7. Thevalve Vid accommodates substantially full ilow from the line 333 to thedrain D7, thereby accommodating the relatively rapid upward movement ofthe neck mold and releasing the container finish from the neck rnold.

The opening of the molds to open L84` de-energizes the solenoid S7 tothereby retract the take-out. 1t will be noted that the energization ofthe relay CRZ to energize the solenoid Sil also energizes relay CRS, andenergization of the relay CRS will introduce a timed operation, undertimer contacts TB7 for maintaining the solenoid S8 energized to maintainclamping pressure upon the containers in the take-out after the take-outhas returned to its normal position. When the timed operation of therelay :CRS expires, the containers are released from the take-out andare removed by gravity or any other suitable way `from the apparatus.

Additionally it will be seen that actuation of the relay CR3, throughits points establishes a circuit through timer contacts TB7 and TAS,thus bridging the gap between timers TMI and TM2 and re-establis'ningtimer TMl as the controlling timer, so that the next cycle may commenceby energization of the solenoid S1 and movement of the neck molddownwardly as heretofore described.

I claim:

l. in a method of making a container of thermoplastic material by theinjection molding of `a container neck in a =mold positioned over anannular orifice, the steps of initially simultaneously moving the neckmold away from the orifice and extruding a tube through said orifice,and varying the rate of neck mold movement to Vary the wall thickness ofthe extruded tube, terminating the 10 extrusion through the oriiice andcontinuing the movement of the neck Imold away from the orice to stretchthe extruded tube while maintaining the relative variations in the wallthickness of the extruded tube.

2. in a method of making an article of plasticized material, the stepsof superimposing a mold over an extrusion orifice, injecting materialinto said mold, allowing said `material to set in said mold, and movingthe mold vertically upwardly away from said orce while ex-trudingthrough said orifice a tubular extension integral with said material insaid mold, said mold being moved from said tube being unsupportedintermediate the mold and the orifice, said orifice `at an initialrelatively slow speed to prevent rupture of the tube as it is initiallyformed and being moved subsequently at a relatively faster speed toextrude lower portions of the tube, the variations in mold movementspeed varying inversely the wall thickness of said tubular extension.

3. in a method of making a container of thermoplastic material by theinjection molding of a container neck in a mold positioned over anAannular orifice, the steps of simultaneously moving the neck mold awayfrom the orifice and extruding through said orifice a tube supported `atone end by its juncture with material in the neck mold and joined at`the other end to material in the orifice, initially moving the neckmold from the orifice slowly to extrude the tube to `a predeterminedwall thickness, `and subsequently moving the neck mold from the oiiliceat a faster rate to extrude the tube to a wall thickness less than saidpredetermined wall thickness.

4. in a lmethod of making an article of plasticized material, the stepsof positioning an injection mold in communication with an orifice,supplying plasticized material to the orice to fill the mold with saidmaterial, allowing said material to set in said mold, simultaneouslysupplying additional material to the orifice and moving the moldlinearly from the orifice to extrude through the orifice a tubeunsupported between the orifice `and the mold, the mold being moved fromsaid orifice at an initial relatively low speed and subsequently ybeingmoved at a relatively faster speed to vaiy the wall thickness of saidtubular extension, interrupting the flow of plastic material toterminate the extrusion, and continuing to move the injection mold awayfrom the orifice to stretch the tube between the mold and the orificewhile maintaining the variations in the wall thickness of the tube.

5. An apparatus for making a blank from which a :blown plastic articleis to be made including means defining an extrusion orifice, aninjection mold movable linearly from a iirst position overlying saidoriiice to a second position spaced 'from said orifice, means forfilling said mold with plastic material at its first position, and meansfor eXtruding a tubular extension integral with the material fillingsaid mold during movement, the improvement of actuating means for movingsaid mold `from its first position to its second position, a pluralityof successively openable means for regulating the speed of movement ofsaid actuating means, `and means responsive to linear displacement ofsaid mold for operating said successively operable means to vary thespeed of movement of said mold.

References Cited in the file of this patent UNITED STATES PATENTS2,657,431 Slaughter Nov. 3, 1953 2,710,987 Sherman June 21, 19552,804,654 Sherman Sept. 3, 1957 2,919,462 Friden Jan. 5,1960

FOREIGN PATENTS 1,029,586 France Mar. 11, 1953

5. AN APPARATUS FOR MAKING A BLANK FROM WHICH A BLOWN PLASTIC ARTICLE ISTO BE MADE INCLUDING MEANS DEFINING A EXTRUSION ORIFICE, AN INJECTIONMOLD MOVABLE LINEARLY FROM A FIRST POSITON OVERLYING SAID ORIFICE TO ASECOND POSITION SPACED FROM SAID ORIFICE, MEANS FOR FILLING SAID MOLDWITH PLASTIC MATERIAL AT ITS FIRST POSITION, AND MEANS FOR EXTRUDING ATUBULAR EXTENSION INTEGRAL WITH THE MATERIAL FILLING SAID MOLD DURINGMOVENMENT, TH IMPROVEMENT OF ACTUATING MEANS FOR MOVING SAID MOLD FROMITS FIRST POSITION TO ITS SECOND POSITION, A PLURALITY OF SUCCESSIVELYOPERABLE MEANS FOR REGULATING THE SPEED OF MOVEMENT OF SAID ACTUATINGMEANS, AND MEANS RESPONSIVE TO LINEAR DISPLACEMENT OF SAID MOLD FOROPERATING SAID SUCCESSIVELY OPERABLE MEANS TO VARY THE SPEED OF MOVEMENTOF SAID MOLD.